Star formation in CALIFA survey perturbed galaxies – I. Effects of tidal interactions

Abstract

We explore the effects of tidal interactions on star formation (SF) by analysing a sample of CALIFA survey galaxies. The sample consists of tidally and non-tidally perturbed galaxies, paired at the closest stellar mass densities for the same galaxy type between subsamples. They are then compared, both on the resolved Star Formation Main Sequence (SFMS) plane and in annular property profiles. Star-forming regions in tidally perturbed galaxies exhibit flatter SFMS slopes compared to star-forming regions in non-tidally perturbed galaxies. Despite that the annular profiles show star-forming regions in tidally perturbed galaxies as being mostly older, their SF properties are never reduced against those ones proper of non-tidally perturbed galaxies. Star-forming regions in non-tidally perturbed galaxies are better candidates for SF suppression (quenching). The lowered SF with increasing stellar mass density in tidally perturbed galaxies may suggest a lower dependence of SF on stellar mass. Though the SFMS slopes, either flatter or steeper, are found independent of stellar mass density, the effect of global stellar mass can not be ignored when distinguishing among galaxy types. Since a phenomenon or property other than local/global stellar mass may be taking part in the modulation of SF, the integrated SF properties are related to the tidal perturbation parameter. We find weak, but detectable, positive correlations for perturbed galaxies suggesting that tidal perturbations induced by close companions increase the gas accretion rates of these objects.

The bimodality in the mass–metallicity relation in SDSS-MaNGA galaxy pairs

“…We find a bimodality -two peaks in the distribution of spaxels in the mass-metallicity space for galaxy pairs -a feature that is not present in the MaNGA sample as a whole. This bimodality was not observed in the study by Morales-Vargas et al (2020), a previous spatially resolved study on perturbed galaxies. 2.…”

“…2 show that while some spaxels in galaxy pairs show a dilution in gas phase metallicity, which is in agreement with the above-mentioned works that investigate the MZR for galaxy pairs, there are also spaxels that do not show diluted metallicities. This bimodality in distribution is not present in Morales-Vargas et al (2020). We looked to see if there were any properties that may show a close relation with the loci of the spaxels.…”

WALLABY Pre-Pilot Survey: The effects of tidal interaction on radial distribution of color in galaxies of the Eridanus supergroup

“…Whether and when the global SFR, the central SFR, and the SFR in the outer disks are boosted or quenched are key signatures that are frequently searched for. It was found that mergers or galactic interactions on average moderately and significantly elevate the total and central SFR of star-forming galaxies (e.g., Mihos & Hernquist 1994;Lisenfeld et al 2007;Morales-Vargas et al 2020; but see Martinez-Badenes et al 2012 for the case in compact groups). The central and total SFR of the primary galaxy (the more massive one) is more strongly elevated if the interacting pair has higher SFR, higher stellar mass, smaller separation, or lower relative velocity (e.g., Zasov & Sulentic 1994;Alonso et al 2004;Bustamante et al 2018).…”